STAR Grant R833417: Fate of Hormones in Tile-Drained Fields and Impact to Aquatic Organisms Under Different Animal Waste Land-Application Practices 2007 - 2010
This study aims to quantify the hormone load in manure and lagoon effluents from tile-drained fields, evaluate hormone persistence in fields after manure application, assess the effects of the discharged hormones on aquatic organisms, and determine the impacts of different types of manure management practices on hormone discharge.
(1) Assess the relative amount of hormones discharged from tile-drained agricultural fields under different manure and lagoon effluent applications; (2) Assess hormone persistence in fields under these application practices; and (3) Evaluate the impacts of these hormone loads (relevant levels and mixtures) on aquatic organisms. We hypothesize that (1) tile drain discharge of manure-borne hormones to receiving waters will be primarily in the first rain events after land-application; (2) hormone degradation in manure- or effluent-amended soils will be rapid compared to persistence in typical anaerobic storage conditions (e.g., manure pit, lagoon), but may be measurably slower when subsurface injected compared to surface applied; and (3) under certain management and environmental conditions, mixtures of synthetic and natural hormones released from animal wastes can be sufficient and persistent enough in aquatic systems to induce irreversible gonadal changes in sensitive life-stages of fish that will persist in adult stages resulting in altered reproduction and population-level effects.
Field monitoring studies will be conducted to evaluate hormone discharges within in-line tile drain or stream collection and monitoring systems associated with agricultural fields receiving animal wastes. Natural and synthetic hormones and their primary metabolites will be measured in manure and effluent being land-applied and in field soils over time. Sexual differentiation and reproduction effects will be evaluated by exposing early life-stages of fish to hormones in controlled laboratory microcosms paired with field studies examining similar endpoints in native populations of fish in streams down gradient from CAFOs and in turtles inhabiting manure retention lagoons. Population-level effects due to hormone exposure will be estimated by fitting a population-matrix model to measured survival and fecundity parameters.
Information obtained will help determine the relationship among different management practices (aerial spraying, subsurface injection, and solid broadcasting) on hormone discharges to aquatic bodies from primarily tile drains. The ecologically-relevant toxicity data generated will be valuable for future risk assessment of aquatic organisms exposed to mixtures of natural and synthetic hormones. The proposed studies will measure population significant endpoints and use relevant lengths, routes, and doses of exposure, which will increase the relevance of the data, and thus, its usefulness in the development of management practices and/or regulations.
Susan Laessig at email@example.com